曲线梁桥在车辆载荷下的动力响应研究

DYNAMIC RESPONSE OF CURVED GIRDER BRIDGE UNDER RANDOM VEHICLE LOADS

近年来随着我国公路交通的快速发展,曲线梁桥被大量工程采用.车辆过桥时的曲线桥振动涉及车辆三向载荷和桥梁弯扭耦合振动,有必要对其进行精确建模并深入研究.本文以某五跨连续曲线箱梁桥为背景,采用ABAQUS有限元软件建立该桥梁的模型,并利用Adams建立了三轴重型汽车整车模型,计算得到了不同工况下的轮胎力.通过编写基于Fortran语言的DLOAD和UTRACLOAD荷载子程序,将六个轮胎载荷作用于曲线桥上,分别进行了不同曲率半径、车速、载重和路面不平顺等条件下的曲线梁桥振动响应计算.研究表明:随着曲率半径的增加,桥梁跨中位移呈现略微下降的趋势;车辆行驶速度对跨中的横向位移及支座的支反力有较大影响;路面不平度等级越高,桥梁竖向挠度及弯矩的冲击效应越大.

When a vehicle crosses the curved bridge,the vibration of the curved bridge is mainly caused by three-direction traffic loads and bending-torsion couplingeffects.In this paper,the finite element model of a five-span continuous curved box girder bridgewas establishedby employing ABAQUS,and a full vehicle model of the three-axle heavy-duty truck was established by using Adams.Six tire forces under different working conditions were calculated,applied onto the curved bridge by developing two subroutines DLOAD and UTRACLOAD.The vibration responses of the curved girder bridge with different curvature radius were calculated under different vehicle speeds,traffic loads and road irregularities.The results showed that with the increase in the curvature radius,the transverse displacement of the bridge at midspan decreases slightly,while the vehicle speed has a significant impact on the transverse displacement and support reaction.Moreover,the higher the grade of road roughness is,the greater the vertical deflection and bending moment of the bridge are.